Floating fire extinguisher



1964 E. D. KAUFMAN ETAL 3,120,273

FLOATING FIRE EXTINGUISHER Filed Jan. 30, 1961 "Wm b 5 mm mm i & ELI! G. If h it 77Zaurzce am BYW,%

United States Patent 3,12%,273 FLGATING FIRE EXTENGUISHER Ernest l). Kaufman, Skolrie, Richard L. Thistlethwaite,

Morton Grove and Priaura'ce G. Hughett, Golf, BL,

assignors to Cook Electric Company, Chicago, 111., a

corporation of Delaware Filed Jan. 30, 1961, Ser. No. 85,697 6 Claims. (Cl. 169-4) This invention relates to a new and improved fire extinguisher adapted to float on the surface of a flammable liquid, such as gasoline, fuel oil or the like, so as to extinguish any fire which may start in the flammable liquid.

One object or" the present invention is to provide a new and improved floating fire extinguisher which operates automatically to generate a fire extinguishing foam, in response to the heat of a fire.

A further object is to provide a new and improved floating fire extinguisher having an upwardly projecting member adapted to generate pressure in an upper reservoir when the member is exposed to the heat of a fire, so that a first liquid in the upper reservoir will be forced past a displaceable element into a lower reservoir containing a second liquid. The liquids may be of well known types adapted to produce fire extinguishing foam chmged with carbon dioxide.

A further object is to provide a new and improved fire extinguisher of the foregoing character in which the lower reservoir is provided with a displaceable wall or cover which gives way when carbon dioxide is generated under pressure in the reservoir, so that the foam will be spread over the surface of the flammable liquid to put out the fire.

Another object is to provide a new and improved floating fire extinguisher which is remarkably simple in construction and low in cost and which may be used in large numbers so as to virtually cover the surface of a flammable liquid contained in a tank, thereby providing complete and automatic fire protection for the tank, Without the necessity for any external fire extinguishing equipment.

Further objects and advantages of the present invention will appear from the following description, taken with the accompanying drawings in which:

FIG. 1 is an elevational view, partly in section, showing a plurality of floating fire extinguishers constructed in accordance with the present invention, the extinguishers being shown in their position of use, floating on the surface of a flammable liquid.

FIG. 2 is a plan view corresponding to FIG. 1 but on a reduced scale, showing a number of the fire extinguishers floating on the surface of a flammable liquid.

FIG. 3 is a fragmentary enlarged sectional view showing the arrangement of the displaceable diaphragm between the upper and lower reservoirs of the tire extinguisher.

As already indicated, FIG. 1 illustrates a plurality of re extinguishers it? adapted to float on the surface of a flammable liquid 12 contained in any suitable tank or the like. The liquid 12 may be gasoline, fuel oil or any other liquid that needs to be protected from fire. A large nun"- ber of the extinguishers it may be provided so as virtually to cover the entire surface of the flammable liquid 12, somewhat as illustrated in FIG. 2. In this Way, the entire tank containing the flammable liquid will be protected. If a fire starts at any point in the liquid, one or more of the the extinguishers ill will be activated automatically by the heat of the fire. The activated extinguishers will generate a fire extinguishing compound so as to put out the fire. In accordance with the usual practice, the fire extinguishing compound is preferably a fire extinguishing foam charged with an inert gas such as carbon dioxide. Such foams are commonly used in extinguishing fires in lammable liquids. The foam spreads over the surface of the liquid to form a blanket which excludes oxygen and thus puts out the fire.

It will be seen that each of the fire extinguishers it comprises a hollow body 14 which is generally in the form of a hemispherical bowl and may be made of plastic, for example. Thus, the body 1 may serve as the lower reservoir to contain one of the foam-forming solutions 16. The other foam-forming solution 13 is contained in an upper reservoir 29 mounted on the upper portion of the body In this case, a fin or other stabflizing member 22 extends downwardly from the body 14. A weight 24 may be mounted on the fin 22 to regulate the buoyancy of the float 1t and to insure that the float will be maintained in an upright position. The buoyancy of the float is regulated so that the body 14 is almost completely submerged in the flammable liquid and thus is largely sheltered from the heat of any fire that may develop in the liquid. Of course, the shape of the hollow body 14 may be varied, the hemispherical shape being largely a matter of convenience.

As shown, the upper end of the bowl-shaped body is closed by a cover or wall 26 which may be in the form of a substantially flat circular disk or plate. The cover 26 may be made of plastic and may be secured to the body in such a manner that the cover will be displaced by the pressure of the carbon dioxide generated in the body when the fire extinguisher is activated. Thus, for example, a layer of pressure sensitive adhesive 28 may be employed to secure the cover as to the upper rim or flange 3% of the bowl-shaped body 14. Such adhesive may comprise a suitable cement, such as an epoxy cement, for example, or may be formed by applying ethylene dichloride or some other suitable softening agent to the plastic parts and 26.

In this case, the upper reservoir or compartment 18 is generally spherical in shape and is formed by opposite generally hemispherical members 32 and 34 on the cover 26. It will be seen that the member 32 projects upwardly from the cover and is generally in the shape of a hemispherical dome. The member 34 is secured to the lower side of the cover 26 and is generally in the shape of a hemispherical bowl or cup.

The dome 3-2 is preferably made of a resinous plastic material and is formed in such a manner that internal tensile stresses will be set up in the wall of the dome. Thus, the dome 32 may be formed from the center portion of the flat cover 26 by a stamping, drawing, or blow ing operation. The plastic material may comprise polymerized methyl methacrylate, for example, commonly sold under the trademarks Lucite and Plexiglas, or various other thermoplastics. The drawing, blowing or stamping of the plastic material produces the internal stresses therein. When subjected to the heat of a fire, the plastic material in the dome 32 is softened, and the internal stresses in the dome then cause the dome to contract. This generates pressure which forces the liquid 18 from the upper reservoir 2% into the lower reservoir 14, past a displaceable element 36 which normally retains the liquid 18 in the upper reservoir 29. It will be seen that the dispiaceable element 36 closes an opening 38 in the lower member 34 of the reservoir 29. This displaceable element may take various forms, but it is preferred to form the displaceable element 36 as a thin rupturable diaphragm which may be made of plastic sheet material, such as cellophane, polyethylene or the like. The diaphragm may be approximately 1 to 5 mils thick. The edges of the diaphragm 36 may be suitably bonded to the lower member 34 around the opening 33.

Instead of providing the rupturable diaphragm 36, the

lower member 34 of the upper reservoir 18 may be lightly bonded to the cover 26 by pressure sensitive adhesive 39 or the like, so that the lower member 34 will be displaced bythe pressure generated in the upper reservoir 2%? when the dome 32 contracts.

The tank of flammable liquid may be completely and automatically protected from fire by providing a large number of the floating fire extinguishers it? in the tmk, so as to'cover virtually the entire surface of the flammable liquid in the tank. if a fire starts at any point in the tank, one or more of the fire extinguishers 320 will be activated. The heat of the fire quickly softens the plastic dome 32 and causes it to contract, due to the internal stresses in the plasticiwall of the dome. This contraction generates sufiicient pressure in the upper reservoir 29 to rupture the thin diaphragm 36. The liquid 1% in the upper reservoir Zil then flows into the opening 38 and mixes with the liquid 16 in the lower reservoir 14-. A large quantity of fire extinguishing foam and carbon dioxide are generated by the reaction between the liquids 16 and 13. The pressure of the carbon dioxide forces the cover 25 off the lower reservoir 14, so that the foam 'can spread over the surface of the flmrnable liquid.

Thus, the foam and the carbon dioxide will quickly smother the fire.

It will be recognized that the fire extinguishers of the present invention are remarkably simple in construction and low in cost. Moreover, the fire extinguishers are easy to install, simply by dropping them in sufiicient numbers into the tank to be protected. The fire extinguishers provide a complete fire protection system, wit out any need for extemal equipment, piping or the like. The body, cover and other parts of the fire extinguishers may be made of plastic materials and thus may be produced very inexpensively.

Various other modfiications, alternative constructions and equivalents may be employed without departing from the true spirit and scope of the invention, as exemplified in the foregoing description and defined in the following claims.

We claim: 7

1. A fire extingmisher, comprising a float having a hol-- low body constituting a first reservoir, a second reservoir mounted on said body and having an upwardly projecting dome constructed to contract when exposed to heat, first and second liquids in said reservoirs and adapted to react to form a fire extinguishing compound when mixed, and a displaceable diaphragm between said reservoirs and adapted to give way in response to pressure in said sec-.

nd reservoir due to contraction of said dome.

2. A fire'extinguisher, comprising a generally hemispherical body adapted to float on the surface of a flammable liquid to be protected from fire, said body being hollow and constituting a first reservoir, a generally flat horizontal upper wall closing the upper end of said body and secured thereto by an adhesive adapted to release said wall from said body in response to the generation of pressure therein, said upper wall having a generally hemispherical dome projecting upwardly therefrom, a generally cup-shaped member secured to said up er wall below said dome, said dome and said cup-shaped member constituting a second reservoir, first and second liquids in said first and secondreservoirs and adapted when mixed to react to form a fire extinguishing foam charged with an inert gas, said dome being internally prestressed and thus being adapted to contract when exposed to the heat of a fire, said cup-shaped member having an opening therein, and a thin rupturable diaphragm covering said opening and adapted to be ruptured by the pressure developed in said second reservoir due to the construction of a d ome,

4% p 3. A fire extinguisher, comprising a float having a gen eraily bowl-shaped body constituting a first reservoir, an upper wall closing said body and adapted to be displaced therefrom by the generation of pressure therein, a second reservoir mounted on said upper wall and having an upwardly projecting dome made of plastic material having internal tensile stress therein, said dome thereby being adapted to contract when exposed to the heat of a fire, first and second liquids in said first and second reservoirs and adapted when mixed to produce fire extinguishing foam charged with carbon dioxide under'pressure, the pressure of the carbon dioxide being efiective to displace said upper wall from said body, and a displaceable dia phragm between said reservoirs and adapted to give way in response to the pressure generated in said second reservoir by the contraction ofsaid dome.

4. A fire extinguisher, comprising a float having a hollow body constituting a first reservoir, a second reservoir mounted on said body and having an upwardly projecting dome constructed to contract when exposed to heat, firstand second liquids in said reservoirs and adapted to react to form a fire extinguishing compound when mixed, and a displaceable element between said reservoirs and adapted to give way in response to pressure in said second reservoir due to contraction of said dome.

5. A fire extinguisher, comprising a float having a body constituting a first reservoir, a cover closing said body and adapted to be displaced therefrom by the gen eration of pressure therein, a second reservoir mounted on the upper portion of said float and having an upward ly projecting dome made of plastic material having internal tensile stress therein, said dome thereby being adapted to contract when exposed to the heat of a fire, first and second liquids in said first and second reservoirs and adapted when mixed to produce fire extinguishing foam charged with carbon dioxide under pressure, the pressure of the carbon dioxide being efiective to displace said cover from said body, and means between said reser/oirs and adapted to give way, in response to the pressure generated in said second reservoir by the contraction of said dome, for releasing said second liquid into said first liquid in said first reservoir.

6. A fire extinguisher, comprising .a body adapted to float on the surface'of a flammable liquid to be protected from fire, said float being hollow and constituting a first reservoir, an upper wall closing the upper end of said body and secured thereto by an adhesive adapted to release said wall from said body in response to the generation of pressure therein, said upper wall having a generally hemispherical dome projecting upwardly therefrom, a member secured to said upper wall below said dome, said dome and said member constituting a second reservoir, first and second liquids in said first and second reservoirs and adapted when mixed to react to forma fire extinguishing foam charged with an inert gas, said dome being internally prestressed and thus being adapted to contract when exposed to the heat of a fire, said mem her having an opening therein, and a thin rupturable diaphragm covering said opening and adapted to be ruptured by the pressure developed in said second reservoir due to the construction of said dome.

References'Cited in the file of this patent UNITED STATES PATENTS 189,987 Austin Apr. 24, 1877 1,671,650 Newman et a1 'May 29, 1928 2,066,546 Smith Jan. 5, 1937 FOREIGN PATENTS 811,944- Great Britain -Q. Apr. 15, 1959 

1. A FIRE EXTINGUISHER, COMPRISING A FLOAT HAVING A HOLLOW BODY CONSTITUTING A FIRST RESERVOIR, A SECOND RESERVOIR MOUNTED ON SAID BODY AND HAVING AN UPWARDLY PROJECTING DOME CONSTRUCTED TO CONTRACT WHEN EXPOSED TO HEAT, FIRST AND SECOND LIQUIDS IN SAID RESERVOIRS AND ADAPTED TO REACT TO FORM A FIRE EXTINGUISHING COMPOUND WHEN MIXED, AND A DISPLACEABLE DIAPHRAGM BETWEEN SAID RESERVOIRS AND ADAPTED TO GIVE WAY IN RESPONSE TOPRESSURE IN SAID SECOND RESERVOIR DUE TO CONTRACTION OF SAID DOME. 